diff --git a/lib/libc/Makefile b/lib/libc/Makefile
--- a/lib/libc/Makefile
+++ b/lib/libc/Makefile
@@ -54,6 +54,13 @@
 CFLAGS+=${CANCELPOINTS_CFLAGS}
 .endif
 
+# Use a more efficient TLS model for libc since we can reasonably assume that
+# it will be loaded during program startup.
+.if ${LIBC_ARCH} == "aarch64" || ${LIBC_ARCH} == "amd64" || \
+    ${LIBC_ARCH} == "i386" || ${LIBC_ARCH} == "riscv"
+CFLAGS+= -ftls-model=initial-exec
+.endif
+
 #
 # Link with static libcompiler_rt.a.
 #